The smart mobile era has opened as smartphones and tablet PCs have become recently more prevalent. While the existing mobile phones were specialized in communication functions, today's smart mobile devices have been developed to have high-performance display functions. As described above, as display functions of mobile devices have been important, input devices and touch functions are complementarily being developed, and obtaining a large area of a display is also becoming an important element.
Touch panels are introduced into smart mobile devices having a large area, and a UV curable transparent adhesive used in this case requires excellent optical characteristics associated with transparency, visibility, and the like together with high adhesive strength. Furthermore, maintaining excellent physical properties of the adhesive under high temperature and high humidity environments for a long period of time is one of the important tasks in imparting excellent durability to mobile devices to which the adhesive is applied, and the like.